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United States Patent |
5,504,202
|
Hutchison
|
April 2, 1996
|
Sucrose polyester useful as fat subtitute and preparation process
Abstract
A process for preparing a sucrose fatty acid polyester comprising mixing a
sucrose ether having an average degree of etherification of from about 4
to about 8 with a basic catalyst and an excess of a fatty acid lower alkyl
ester, heating the resultant mixture to a temperature of from about
120.degree. C. to about 180.degree. C. at a pressure of up to about 10 mm
of mercury while removing the alcohol formed during the formation of the
sucrose fatty acid polyester, and then separating the sucrose fatty acid
polyester from the reaction mixture. The sucrose fatty acid polyester is a
synthetic low calorie fat substitute and is useful in preparing edible
non-digestible food products.
Inventors:
|
Hutchison; Robert B. (Cincinnati, OH)
|
Assignee:
|
Henkel Corporation (Plymouth Meeting, PA)
|
Appl. No.:
|
223203 |
Filed:
|
April 5, 1994 |
Current U.S. Class: |
536/124; 426/601; 426/611; 426/804; 536/115; 536/116; 536/119; 536/120; 554/168 |
Intern'l Class: |
C08B 037/00; C07H 013/06; C07H 013/00 |
Field of Search: |
536/115,116,119,120,124
426/601,611,804
554/168
|
References Cited
U.S. Patent Documents
3600186 | Aug., 1971 | Mattson | 536/124.
|
3963699 | Jun., 1976 | Rizzi et al. | 536/124.
|
4005195 | Jan., 1977 | Jandacek | 536/124.
|
4034083 | Jul., 1977 | Mattson | 536/124.
|
4611055 | Sep., 1986 | Yamamoto et al. | 536/119.
|
4880657 | Nov., 1989 | Guffey et al. | 426/611.
|
4931552 | Jun., 1990 | Gibson et al. | 536/119.
|
4954621 | Sep., 1990 | Masaoka et al. | 536/119.
|
5071669 | Dec., 1991 | Seiden | 426/611.
|
5077073 | Dec., 1991 | Ennis et al. | 536/116.
|
5079355 | Jan., 1992 | Grechke et al. | 536/119.
|
5085884 | Feb., 1992 | Young et al. | 426/611.
|
5194281 | May., 1992 | Johnston et al. | 536/119.
|
5236733 | Aug., 1993 | Zimmerman et al. | 426/611.
|
5314707 | May., 1994 | Kester et al. | 426/611.
|
5366753 | Nov., 1994 | Meyer et al. | 426/611.
|
Primary Examiner: Griffin; Ronald W.
Attorney, Agent or Firm: Szoke; Ernest G., Jaeschke; Wayne C., Grandmaison; Real J.
Claims
What is claimed is:
1. The process of preparing a sucrose fatty acid polyester comprising
mixing a sucrose ether having an average degree of etherification of from
about 3 to about 8 with a basic catalyst and an excess of a fatty acid
lower alkyl ester, heating the resultant mixture to a temperature of from
about 120.degree. C. to about 180.degree. C. at a pressure of up to about
10 mm of mercury while removing the alcohol formed during the formation of
said sucrose fatty acid polyester, and then separating said sucrose fatty
acid polyester from the reaction mixture.
2. A process as in claim 1 wherein said sucrose ether has an average degree
of etherification of from about 3 to about 6.
3. A process as in claim 1 wherein said lower alkyl ester comprises a
C.sub.1 -C.sub.4 alkyl ester of a fatty acid containing 6 to 22 carbon
atoms.
4. A process as in claim 1 wherein said lower alkyl ester comprises a fatty
acid methyl ester.
5. A process as in claim 4 wherein said methyl ester is derived from a
fatty acid selected from the group consisting of saturated fatty acids,
unsaturated fatty acids, and mixtures thereof.
6. A process as in claim 1 wherein from about 4 to about 15 moles of said
fatty acid lower alkyl ester is used per mole of said sucrose ether.
7. A process as in claim 1 wherein said catalyst is selected from the group
consisting of an alkali metal carbonate, alkali metal hydroxide, alkali
metal lower alkoxide, and alkali metal hydride.
8. A process as in claim 1 wherein said catalyst is present in said mixture
in an amount of from about 0.10 to about 0.20 percent by weight, based on
the weight of said fatty acid lower alkyl ester.
9. A process as in claim 1 including bleaching said sucrose fatty acid
polyester.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a process for the preparation of sucrose fatty
acid polyesters and the resultant products; and more specifically, to the
use of partially etherified sucrose as feedstock in the process. The
products are particularly useful as synthetic low calorie fat substitutes
for replacing triglyceride fats in food compositions.
The consumption of large amounts of triglyceride fats has been linked to
various health problems. For example, one of the most common metabolic
problems among people today is obesity. This condition is primarily due to
ingestion of a greater number of calories than are expended. Fat is the
most concentrated form of energy in the diet, with each gram of fat
supplying approximately nine calories, and triglyceride fats constitute
about 90% of the total fat consumed in the average diet.
In a U.S. government study, it has been reported that elevation of blood
cholesterol levels is a major cause of coronary artery disease, and
recommended a reduction in the amount of fat eaten to reduce blood serum
cholesterol levels. Thus, there is a need for ways to reduce the amount of
triglyceride fats in the diet, in order to reduce the health risks
associated with these fats.
2. Discussion of Related Art
Sucrose fatty acid esters are conventionally prepared by transesterifying a
lower alkyl ester of higher fatty acids with sucrose. Since sucrose has
eight hydroxyl groups per molecule, the number of fatty acid groups bound
to sucrose per molecule, commonly referred to as the degree of
substitution (D.S.), may vary from 1 to 8. Among them, mono-, di-, and
tri-esters find use as non-toxic, biodegradable surfactants and are
commercially available in large quantities.
The various known methods for producing sucrose fatty acid esters may be
classified into three principal types; i.e., the solvent process, the
microemulsion process, and the direct or solvent-free process.
In the solvent process, a fatty acid ester is transesterified with sucrose
in a common solvent for the fatty acid ester and sucrose such as
dimethylformamide or dimethylsulfoxide in the presence of a basic
transesterification catalyst. The reaction may be carried out at a
relatively lower temperature, for example, at about 90.degree. C. This
process suffers from certain disadvantages in that the solvent used is
toxic and, therefore, must be completely removed after the reaction. This
is possible in practice only with great difficulty.
In the second process generally known as "microemulsion process", a fatty
acid ester is dispersed in a solution of sucrose in a solvent such as
propylene glycol or water with the aid of an emulsifier such as alkali
metal fatty acid soaps to form a microemulsion, and then the solvent is
removed from the emulsion. The reaction is carried out in the absence of
solvent and the reaction product does not contain any solvent. Great
difficulty is also present in this process for removing the solvent while
maintaining the microemulsion state.
In the third process, sucrose is directly reacted with a fatty acid ester
by heating their mixture. This process is known as "direct process" or
"solvent-free process". Since sucrose and fatty acid esters do not have
sufficient affinity to each other, the success of this direct process
depends on how well they are contacted in the reaction system. To this
end, most of known processes employ an alkali metal fatty acid soap either
directly added to or formed in situ in the reaction system to produce a
homogeneous molten mixture of reactants.
Consequently, the reaction mixture from the microemulsion process or direct
process contains a relatively large amount of alkali metal fatty acid
soap, since the soap itself is not a reactant and remains unreacted during
the transesterification reaction.
A relatively small amount of alkali metal fatty acid soap is unavoidably
formed even in the solvent process by the reaction between the fatty acid
ester and the transesterification catalyst such as alkali metal hydroxides
and carbonates.
Normally, alkali metal fatty acid soaps remaining in the reaction mixture
are separated from sucrose fatty acid esters, while their presence may be
tolerated in certain uses such as detergents.
Sucrose fatty acid polyesters may be produced by the following published
microemulsion process or solvent-free process.
U.S. Pat. No. 3,963,699 to Rizzi et al. discloses a process for producing
sucrose fatty acid polyesters. According to this process, a mixture of
sucrose, a fatty acid lower alkyl ester, an alkali metal fatty acid soap
and a basic catalyst is heated in the first step to form a homogeneous
melt. Thereafter, excess fatty acid lower alkyl esters are added in the
second step to the reaction product of the first step. This process
suffers from certain disadvantages in that it requires basic
transesterification catalysts such as alkali metals, alloys of alkali
metals, alkali metal hydrides or alkali metal alkoxides which are
expensive and dangerous in handling. The two step reaction is cumbersome
in operation and necessarily requires a prolonged reaction time which can
lead to the risk of darkening of the reaction mixture.
Generally, sucrose fatty acid esters having a D.S. of greater than 2 are
produced by controlling the molar ratio of fatty acid lower alkyl esters
to sucrose. Up to a D.S. of 5, polyesters may be prepared at the ratio of
fatty acid esters approximately equal to or slightly in excess of
theoretical amounts. However, polyesters having a D.S. of greater than 5
require further amounts of fatty acid lower alkyl esters. For example,
polyesters having a D.S. of 5.5, 6 and 7 or higher may only be produced at
the ratio of fatty acid esters of 6, 8 and 10 moles per mole of sucrose,
respectively.
Thus, it is critical for the industrial production of sucrose fatty acid
polyesters to minimize the amount of fatty acid lower alkyl esters. The
presence of large amounts of fatty acid lower alkyl esters in the reaction
system at one time produces certain unique problems. A reaction system
containing a large amount of fatty acid esters is less viscous and thus
easily susceptible to phase separation which adversely affects the
transesterification reaction. Furthermore, relatively large amounts of low
boiling point by-products such as methanol are generated and vigorous
foaming of reactants takes place during the initial period of the
reaction.
Fatty acid lower alkyl esters may be removed from the reaction product by
solvent extraction using a solvent such as methanol in which sucrose fatty
acid esters are relatively insoluble and fatty acid lower alkyl esters are
soluble. However, this technique requires a large amount of solvent. For
example, about 40 times of methanol are used relative to the sucrose fatty
acid ester in the previously cited Rizzi et al. Patent. This is, of
course, uneconomical and requires a large amount of investment for the
solvent recovery system and anti-explosion facilities. Additionally,
certain amounts of sucrose fatty acid esters dissolving in the solvent are
unavoidably wasted.
Sucrose fatty acid polyesters are known as suitable low-calorie fat
replacers in edible products. Substantially indigestible by human beings,
they have physical and organoleptic properties very similar to
triglyceride oils and fats conventionally used in edible products as
described, for example, in U.S. Pat. Nos. 3,600,186, 4,005,195 and
4,034,083. In addition, U.S. Pat. No. 5,077,073 discloses ethoxylated
sugar or sugar alcohol sucrose fatty acid esters useful as fat substitutes
wherein from 1 to 50 alkoxyl groups are attached by ether linkages to each
polyol molecule. However, the use of sucrose fatty acid polyesters which
are liquid below body temperature (about 37.degree. C.) has been reported
to result in an undesired laxative effect and give rise to the problem of
anal leakage. Thus to overcome this problem, it has been proposed to
introduce considerable amounts of solids in the sucrose polyester phase by
adding solid fatty acids, or employing a polyester which is partially
liquid and partially solid at body temperature.
It is accordingly a main object of this invention to provide a process for
producing sucrose fatty acid polyesters in an efficient manner which is
free from the above-described disadvantages and which is simple in
operation and easy to control.
DESCRIPTION OF THE INVENTION
Other than in the operating examples, or where otherwise indicated, all
numbers expressing quantities of ingredients or reaction conditions used
herein are to be understood as modified in all instances by the term
"about".
It has now been found that sucrose fatty acid polyesters may be produced
via a transesterification reaction by utilizing partially etherified
sucrose as feedstock in combination with a fatty acid lower alkyl ester to
prepare sucrose polyesters useful as synthetic low calorie fat substitutes
in foods. Sucrose ethers are mixtures of mono- to octa-octyl ethers of
sucrose. The sucrose ethers may be obtained by the telomerization reaction
of butadiene with sucrose to give the respective octadienyl ethers, and
subsequent hydrogenation to the saturated product, wherein the average
degree of substitution or etherification (average number of octyl
groups/sucrose) can be varied by changing the ratio of butadiene and
sucrose during the reaction. The use as a reactant of partially etherified
sucrose having a minimum degree of substitution enables sufficient oil
solubility to allow for facile reaction with fatty acids, fatty acid
esters or triglycerides to produce the desired sucrose polyester.
In accordance with this invention, sucrose fatty acid polyesters are
prepared from sucrose ethers having an average degree of etherification of
about 4, i.e., about 50% of the hydroxyl groups are etherified, although
the degree of etherification may range from 1 to 8, it is preferably 3 to
6.
Thus, in a broad sense, the process of this invention comprises mixing a
sucrose ether having an average degree of etherification of about 3 to 6,
preferably about 4, with a basic catalyst and an excess of a fatty acid
lower alkyl ester, heating the mixture to a temperature of from about
120.degree. C. to about 180.degree. C. at a pressure of up to about 10 mm
of mercury while removing the alcohol formed during the formation of the
sucrose fatty acid polyesters, and then separating the sucrose fatty acid
polyesters from the reaction mixture. Separation can be accomplished by
any of the separation procedures routinely used in the art. Distillation,
water washing, conventional refining techniques or solvent extraction are
preferred due to their simplicity and economy. The product may also be
bleached, if desired, with a bleaching agent. The sucrose ethers may be
esterified to a degree of close to 100%.
The term "sucrose fatty acid polyesters" as used herein refers to these
having an average degree of substitution of about 4 to about 8.
Esters of lower alcohols, preferably C.sub.1-4 alcohols, are suitable for
use as fatty acid lower alkyl esters. The term "fatty acid lower alkyl
esters" as used herein is intended to include the C.sub.1 to C.sub.4 alkyl
esters of fatty acids containing 6 to 22 carbon atoms., The fatty acids
may be saturated or unsaturated and may have a straight or branched chain.
Mixtures of fatty acid esters may also be used. From 4 to 15 moles,
preferably from 8 to 15 moles of fatty acid lower alkyl esters per mole of
sucrose ether are used. Methyl esters are the preferred fatty acid esters
for use herein, since their use in the process tends to result in
unusually high yields of sucrose fatty acid polyesters.
Examples of suitable fatty acids containing 6 to 22 carbon atoms include
caprylic, capric, lauric, myristic, myristoleic, palmitic, palmitoleic,
stearic, oleic, ricinoleic, linoleic, linolenic, eleostearic, arachidic,
arachidonic, behenic and erucic acid. The fatty acids can be derived from
naturally occurring or synthetic fatty acids, they can be saturated or
unsaturated, including positional and geometrical isomers. The fatty acids
esterified to the sucrose ether molecule are preferably of mixed carbon
chain length to produce the desired physical properties.
In a preferred embodiment of this invention, the fatty acid residues of the
non-digestible sucrose polyesters contain less than about 10 wt. % fatty
acid residues having a carbon chain length of 10 or less. It has
furthermore been found beneficial to include a significant amount of fatty
acid residues having a carbon chain length of 13 to 17, and to select the
majority of fatty acid residues from those having a carbon chain length of
14 to 18 carbon atoms. Accordingly, it is preferred that at least 50 wt. %
of the fatty acid residues of the non-digestible sucrose fatty acid
polyesters have a carbon chain length of 13-17, and more preferably more
than 50 wt. % of the fatty acid residues have a carbon chain length in the
range of 14-18. In addition, it is also preferred that less than 10 wt %,
more preferably less than 5 wt % of the fatty acid residues in the
non-digestible sucrose fatty acid polyesters of this invention have a
carbon chain length of 20 or more.
The physical properties of sucrose polyesters, like those of triglyceride
fats, depend on the fatty acids used in preparation of the material. The
fatty acids esterified to the sucrose ether dictate the physical
properties of the resulting fat substitute ranging from a liquid to a
solid. For example, sucrose polyester made from safflower oil fatty acids
(C.sub.18) is a free-flowing liquid similar to safflower oil. By
comparison, sucrose polyester made from a completely saturated long-chain
fat, e.g. lard, is a high-melting solid at room temperature. Generally,
sucrose fatty acid polyesters are virtually identical in physical
properties to a triglyceride with the same fatty acids. Taste, appearance,
aroma and immiscibility with water are indistinguishable from
triglyceride. It is these properties, along with their non-absorption,
i.e., resistance to pancreatic lipase activity, which give sucrose fatty
acid polyesters their unique qualities and value as non-calorie fats or
oils for use in foods. Thus, sucrose polyesters provide the perception of
fat to foods without delivering the calories normally assimilated when
triglycerides are consumed.
In the preparation process of the sucrose fatty acid polyesters of this
invention, examples of basic transesterification catalysts include alkali
metal carbonates such as potassium carbonate and sodium carbonate, alkali
metal hydroxides such as potassium hydroxide and sodium hydroxide, and
alkali metal lower alkoxides such as potassium methoxide and sodium
ethoxide, and alkali metal hydrides. Sodium hydride is a preferred
catalyst because better results have been obtained therewith in the
process of this invention. The catalyst is added to the reaction mixture
in an amount of from about 0.10 to about 0.20%, preferably about 0.15% by
weight of fatty acid lower alkyl ester. The fatty acid lower alkyl ester
serves also as a carrier or dispersing agent for the catalyst to insure
uniform distribution of the catalyst throughout the reaction mass.
Methanol may also serve as a carrier or dispersing agent for the catalyst.
The transesterification reaction may be carried out by heating the reaction
mixture at a temperature of 120.degree. C. to 180.degree. C., preferably
from 140.degree. C. to 160.degree. C., under a vacuum less than 10 mm Hg
with stirring at a linear speed of 1 to 50 m/second, preferably from 2 to
20 m/second.
The length of reaction time varies with the reaction conditions and
,generally requires only 1 to 3 hours.
As previously noted, as the transesterification reaction proceeds, a lower
alcohol is formed as a by-product. In order to promote the reaction, the
alcohol by-product is preferably removed. Many removal techniques are
known in the art, and any one of them can be used to effectively and
efficiently remove the lower alcohol. Vacuum removal both with and without
an inert gas sparging has been found to promote the reaction. In any
event, the formation of a lower alcohol presents no significant obstacle
to the use of the process in the food industry.
As used herein, the term "non-digestible" means being absorbable to an
extent of 70% or less, and particularly 20% or less, by the human body
through its digestive system.
The edible composition according to the present invention may contain in
addition to the sucrose fatty acid polyesters minor ingredients
conventionally found in frying oils including anti-foams, such as silicon
oils, anti-spattering agents, anti-oxidants, such as naturally present or
added tocopherols, butylated hydroxytoluene, -anisole or -quinone, acids
such as citric acid, ascorbic acid, flavouring agents, and the like.
The sucrose fatty acid polyesters of this invention may be present in
compositions such as frying fats, cooking oils, shortenings, margarines,
spreads, ice cream, dressings, and the like. The sucrose polyesters are
particularly suitable for shallow and deep frying purposes. Thus, another
aspect of this invention is the use of the instant sucrose fatty acid
polyesters for preparing fat-containing edible food products wherein the
process involves heat treating at least part of such food products with a
fluid fat comprising said polyester composition at a temperature of more
than about 100.degree. C. When using the present composition in, for
instance, deep frying or shallow frying food products, the products will
not rapidly develop a solid fat layer after having been taken out of the
hot oil. In some cases, it may be advantageous to combine the sucrose
polyesters of this invention with relatively low melting glyceride fats
having a melting temperature below body temperature because such
combinations provide products that exhibit no drip-off problems and have
very good frying properties. In such case, the frying fat composition may
comprise from 70% to 90% by weight of the sucrose fatty acid polyesters
and from 10% to 30% by weight of glyceride fats. Suitable glyceride oils
and fats include those optionally modified by partial hydrogenation and/or
fractionation to provide the required melting characteristic, such as
coconut oil, palmkernel oil, palm oil, butter fat, soybean oil, safflower
oil, cotton seed oil, rapeseed oil, poppy seed oil, corn oil, sunflower
oil, tallow, lard and mixtures thereof. Of these oils, palm oil, partially
hardened rapeseed oil and partially hydrogenated soybean oil are
preferred. Accordingly, another aspect of this invention is edible fried
food products that have been fried in a frying fat or oil composition
pursuant to the invention. Food products which can suitably be fried in
the present frying fat composition include: potato crisps (french fries),
potato and corn chips, fried snacks, fried chicken, meat and fish
products, battered and crumbed fish and meat products such as e.g. fish
sticks and the like. At the point of sale these food products may either
be fully baked, or be in a frozen pre-fried condition requiring further
preparation by oven or microwave.
The invention is further illustrated by the following example, but it is
not intended to be limited thereby.
The following reaction was carried out in a 1 liter 3-neck flask containing
a stirrer, thermometer, reflux condenser, and vacuum outlet.
EXAMPLE
A sucrose ether having an average degree of etherification of about 4, and
about 50% excess of a methyl oleate esterifying agent were degassed, and
about 0.16%/wt. of a sodium hydride catalyst was added thereto. After
evolution of hydrogen gas had stopped, the mixture was heated to a
temperature of about 85.degree. C. under a nitrogen blanket for about 11/2
hours. After most of the methanol had distilled off, high vacuum at about
135.degree. C. was applied for about 2 hours to remove the remaining
methanol. The product was cooled to about 25.degree. C. and extracted with
methyl alcohol to remove excess methyl oleate. The product having a light
brown color, was bleached to a light yellow color using grade 160 filtrol
(clay).
The following examples illustrate lipase enzyme assay used as a screening
test for animal feeding studies.
A stabilized test oil emulsion is incubated overnight with lipase and
buffer of pH 8.0. The test oil is hydrolyzed by pancreatic lipase to fatty
acids, diglycerides and to a small extent monoglycerides and glycerol. The
fatty acids liberated in the reaction are titrated with 0.050N NaOH to a
pH of 10.5.
In a 15.times.45 mm, 4 ml vial are combined the following: 0.5 ml H.sub.2
O; 0.5 ml of 7 percent(w/v) gum acacia (gum arabic); 0.5 ml of candidate
oil and 0.2 ml of 0.2M tris buffer pH 8.0 (tris(hydroxymethyl)
aminomethane which is available from Sigma Chemical Co., St. Louis, Mo.).
To save time and steps, in practice, the water, gum acacia, and buffer are
combined into a stock solution (10-20 ml) and an aliquot of 1.2 ml of this
mixture is added to 500 microliters of test oil in the vial. Each test run
will contain a sample of olive oil emulsion prepared in the same way which
serves as a positive control to determine the activity of the lipase and
the effectiveness of the emulsification.
The contents of each vial are then sonicated for no more than 10 cycles
(power=4; duty=50 percent) in a Tekmar sonic disrupter (Tekmar Company,
Cincinnati, Ohio) equipped with a standard microtip probe. The probe is
wiped between samples with a Kimwipe moistened with EtOH or CHCl.sub.3.
The result is a stable, creamy white emulsion. Eight each 135 microliter
samples are distributed to 21.times.70 mm. 16 ml sc vials. The four test
vials receive 10 uL each of a cocktail containing 10 percent w/v of each
of the following lipases in deionized water: lipase N, lipase G and lipase
D (available from Amano International Enzyme Co., Inc., P.O. Box 1000,
Troy, Va. 22974). The blanks receive no enzyme at this stage. All of the
vials are capped and incubated overnight at 37.degree. C. The unused
lipase stock is also capped and incubated overnight at 37.degree. C. This
permits any enzymatic reactions which might alter pH to take place.
For each day's titration, a fresh one liter batch of 0.05N NaOH is prepared
by diluting 1:10 a 100 ml sample of purchased 0.5N NaOH reagent. The 0.05N
NaOH is also standardized against a 0.1N HC1 sample by titration to pH
7.0. All of these steps ensure the accuracy of the titration data.
For each sample of oil, the eight tubes are removed from the 37.degree. C.
incubator. Each tube receives the addition of a 3/8 inch diameter TFE
starburst stirring head (available from Fisher Scientific Co.) magnetic
stirrer and 4.0 ml of H.sub.2 O to increase the volume and allow the pH
electrode to be submerged. The four "blank" tubes receive 10 microliters
of the overnight incubated lipase stock solution immediately prior to
titration.
All samples are then titrated to pH 10.5 in a Fisher Computer Aided
Titrimeter equipped with a Gel-Filled Polymer Body Combination pH
electrode (available from Fisher Scientific Co.). The average number of
mls added to the blank sample are subtracted from the average number of ml
added to the test sample to determine the mL OH required to neutralize the
acid from 50 microliters of oil.
From the determined value of density for the oil, a value of lipase
liberated milliequivalents of acid per gram of oil is computed. This value
is divided by the value for total available acid determined by
saponification of a measured mass of test oil. From this ratio, a value
for percent lipase hydrolysis is computed. The results are summarized in
Table 1.
TABLE 1
______________________________________
Lipase Hydrolysis Test Results
% Lipase
Hydrolysis
Sample (1 hour) (18 hours)
______________________________________
Sucrose ether methyl oleate
1-2 1-2
polyester
Control-olive oil 53-55 73-75
______________________________________
The above-identified sucrose polyester was tested for its minimal
absorption potential as a non-nutritive substance. The criteria for a
non-nutritive oil are that a successful candidate will be safe for human
consumption, be less than 40% absorbed, not cause anal leakage at
projected exposures, and exhibit thermal stability for use in fried foods.
These beneficial qualities in a food oil will provide the consumer with a
new product that has the potential to lower fat intake and thereby lower
the high caloric consumption perceived with fried foods, e.g. snack foods.
Test Materials and Methods
An intact biological system (live animal) is required to study the
interaction of digestion, absorption, and metabolism by various organs.
Fischer 344 rats were chosen as the animal model due to the extensive,
historical toxicological experience with this rat strain. After arrival,
the animals were held for one week to acclimate to the change in living
environment, and one week for diet habituation prior to the actual test
phase. Three dose levels, 2.5%, 5.0%, and 7.5%, of the test compound were
evaluated for a two-week study period. Body weight gain and food
consumption were monitored throughout the two-week test period. Feces were
collected from the low-dose groups during the second study week for
determination of oil absorption using Soxhlet oil analysis. Upon
termination, a gross necropsy was performed to reveal any evidence of
gross pathological changes that occurred while the test compound was fed.
Samples of blood serum were taken for hematology and clinical chemistry
analysis. The blood serum and livers were analyzed by TLC for the presence
of test oil. This study was intended as a discovery screening vehicle and
was not conducted according to GLP guidelines. The study was conducted in
all aspects with sound scientific practices.
Results and Discussion
The absorption data were corrected for the actual quantity of oil in the
diet. Spiking of control fecal samples revealed that all test oils were
adequately recovered (average of greater than 92% recovery) by Soxhlet oil
analysis.
The sucrose polyester met the criteria for less than 40% absorption. No
deaths occurred during the two-week testing period. No evidence of gross
toxicity was observed with the test oil. Unusual vasodilation was observed
in association with the reproductive organs of both sexes. Females from
two dose groups were observed to have unusually vascularized ovarian
follicles, or a blood engorged (hematoma) ovary. Further studies would
necessitate an indepth histological and pathological evaluation of this
phenomena, to determine its biological significance. However, it is known
that certain of the impurities (especially fatty acid methyl esters) may
exhibit activity on smooth muscles, particularly vascular smooth muscle,
and thus these results may be secondary to the presence of impurities.
Animals in all test groups (including control animals) exhibited lymphoid
Peyer's patch hyperplasia, a nonspecific immune response. Although the
antigenic agent causing this response is unknown, this common finding
should not affect the data interpretation.
Liver to body weight ratios were lower than controls for the high dose male
groups. Higher liver to body weight ratios than controls were observed in
the medium dose group. These findings (which are virtually opposite and
thus not dose-response related) are not coupled with significant changes
in the liver enzyme activities associated with toxicity, and are therefore
probably of little biological significance.
No differences were observed in spleen weights or spleen to body weight
ratios. Body weights and weight gain were monitored throughout the study.
No differences were observed between termination body weights (within the
same sex groups). No differences were observed between the rates of growth
(within the same sex groups).
Fecal weights were found to be higher in males with poorly absorbed sucrose
polyester. Anal leakage was present in the high dose group of the test
compound. Nonabsorption of the test oil appeared to be not the only
contributing factor to anal leakage in this study. Other undetermined
factors also appear to have played a key role.
Food consumption was monitored during the study, and the data were used to
calculate feed efficiency. More food was consumed by the animals in the
high dose sucrose polyester group than the controls. Evaluation revealed a
reduction in feed efficiency for the high dose male group. This is
probably a reflection of the severe anal leakage observed in this group.
A few statistically significant differences were observed with clinical
chemistry values analysis. One significant effect observed with males fed
the sucrose polyester was a reduction in total protein levels. This
reflects a drop in the quantity of proteins circulating in the blood
serum. Serum albumin is the major protein constituent of blood serum;
however, its titer was unchanged. Therefore, the changes in blood protein
are probably due to other components, possibly acid glycoprotein or immune
system constituents. The magnitude of the change, however, is small (about
6%) and no comparable change was found in females. Thus, the biological
significance of this change is unknown.
No test compound was detected by TLC analysis of extracts made from blood
serum and liver with a detection limit of 0.5% (v/v). This implies that
any absorbed test material was extensively metabolized.
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